Re: [PATCH v1 2/2] leds: trigger: gpio: Convert to use kstrtox()

[Jacek Anaszewski <jacek.anaszewski@gmail.com>]

Hi Andy,

Thank you for the patch.

On 8/21/19 7:17 PM, Andy Shevchenko wrote:
> sscanf() is a heavy one and moreover requires additional boundary checks.
> Convert driver to use kstrtox() and replace kstrtoul() by kstrtobool() in
> gpio_trig_inverted_store()
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  drivers/leds/trigger/ledtrig-gpio.c | 23 ++++++++++-------------
>  1 file changed, 10 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/leds/trigger/ledtrig-gpio.c b/drivers/leds/trigger/ledtrig-gpio.c
> index 31f456dd4417..b01862b94c99 100644
> --- a/drivers/leds/trigger/ledtrig-gpio.c
> +++ b/drivers/leds/trigger/ledtrig-gpio.c
> @@ -57,13 +57,13 @@ static ssize_t gpio_trig_brightness_store(struct device *dev,
>  		struct device_attribute *attr, const char *buf, size_t n)
>  {
>  	struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
> -	unsigned desired_brightness;
> +	u8 desired_brightness;
>  	int ret;
>  
> -	ret = sscanf(buf, "%u", &desired_brightness);
> -	if (ret < 1 || desired_brightness > 255) {

LED_FULL (255) is already not a hard limit for quite a long time.
While we are at it we could change that to led->max_brightness.

> +	ret = kstrtou8(buf, 10, &desired_brightness);
> +	if (ret) {
>  		dev_err(dev, "invalid value\n");
> -		return -EINVAL;
> +		return ret;
>  	}
>  
>  	gpio_data->desired_brightness = desired_brightness;
> @@ -86,16 +86,13 @@ static ssize_t gpio_trig_inverted_store(struct device *dev,
>  {
>  	struct led_classdev *led = led_trigger_get_led(dev);
>  	struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
> -	unsigned long inverted;
> +	bool inverted;
>  	int ret;
>  
> -	ret = kstrtoul(buf, 10, &inverted);
> -	if (ret < 0)
> +	ret = kstrtobool(buf, &inverted);
> +	if (ret)
>  		return ret;
>  
> -	if (inverted > 1)
> -		return -EINVAL;
> -
>  	gpio_data->inverted = inverted;
>  
>  	/* After inverting, we need to update the LED. */
> @@ -122,10 +119,10 @@ static ssize_t gpio_trig_gpio_store(struct device *dev,
>  	unsigned gpio;
>  	int ret;
>  
> -	ret = sscanf(buf, "%u", &gpio);
> -	if (ret < 1) {
> +	ret = kstrtouint(buf, 10, &gpio);
> +	if (ret) {
>  		dev_err(dev, "couldn't read gpio number\n");
> -		return -EINVAL;
> +		return ret;
>  	}
>  
>  	if (gpio_data->gpio == gpio)
> 

-- 
Best regards,
Jacek Anaszewski